Combined PDFs in Preview have different page sizes
I have a multipage PDF containing 8.5x11 pages. I scanned a new 8.5x11 page to a new PDF, opened both files in Preview and dragged the single page thumbnail from the new file into the preexisting file's thumbnail panel. The page was added to the target file and can be saved, but the newly inserted page image is much too large; I want it to conform to the letter-size pages in the target PDF. Not sure how to adjust the page or image size.
I'm scanning from an older HP printer/scanner to a Macbook Air running Ventura 13.5.2.
MacBook Air 13″, macOS 13.5